Model Reduction for the Chemical Master Equation: an Information-Theoretic Approach

The complexity of mathematical models in biology has rendered model reduction an essential tool in the quantitative biologist's toolkit. For stochastic reaction networks described using the Chemical Master Equation, commonly used methods include time-scale separation, the Linear Mapping Approximation and state-space lumping. Despite the success of these techniques, they appear to be rather disparate and at present no general-purpose approach to model reduction for stochastic reaction networks is known. In this paper we show that most common model reduction approaches for the Chemical Master Equation can be seen as minimising a well-known information-theoretic quantity between the full model and its reduction, the Kullback-Leibler divergence defined on the space of trajectories. This allows us to recast the task of model reduction as a variational problem that can be tackled using standard numerical optimisation approaches. In addition we derive general expressions for the propensities of a reduced system that generalise those found using classical methods. We show that the Kullback-Leibler divergence is a useful metric to assess model discrepancy and to compare different model reduction techniques using three examples from the literature: an autoregulatory feedback loop, the Michaelis-Menten enzyme system and a genetic oscillator

Training deep neural density estimators to identify mechanistic models of neural dynamics

Mechanistic modeling in neuroscience aims to explain observed phenomena in terms of underlying causes. However, determining which model parameters agree with complex and stochastic neural data presents a significant challenge. We address this challenge with a machine learning tool which uses deep neural density estimators-- trained using model simulations-- to carry out Bayesian inference and retrieve the full space of parameters compatible with raw data or selected data features. Our method is scalable in parameters and data features, and can rapidly analyze new data after initial training. We demonstrate the power and flexibility of our approach on receptive fields, ion channels, and Hodgkin-Huxley models. We also characterize the space of circuit configurations giving rise to rhythmic activity in the crustacean stomatogastric ganglion, and use these results to derive hypotheses for underlying compensation mechanisms. Our approach will help close the gap between data-driven and theory-driven models of neural dynamics

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

The clinico-radiological spectrum of Dyke-Davidoff-Masson syndrome in adults

PMID = 2873375

Dimensional approach to obsessive-compulsive disorder: Dimensional obsessive-compulsive scale with Turkish psychometric properties

Objective: The Dimensional Obsessive Compulsive Scale (DOCS) is a measurement tool that examines the severity of thematically distinct symptom domains of obsessive compulsive disorder (OCD). In this study we assess psychometric properties of the Turkish version of DOCS. Methods: Ninety-six patients who presented consecutively to the Dişkapi Yildirim Beyazit Teaching and Research Hospital outpatient unit and who were diagnosed with OCD according to the DSM-IV-TR criteria were enrolled in the study. The DOCS, Yale-Brown Obsessive Compulsive Scale (YBOCS), and Padua Inventory (PI) were completed by the participants. Internal consistency was estimated using Cronbach's Alpha values and item-total correlations. Principal component analyses with Varimax rotation were used to assess latent factor structure . Results: Explanatory Factor Analyses (EFA) revealed a 4-factor solution for the DOCS. Chronbach's alpha values for the whole scale, "contamination" sub-scale, "responsibility" sub-scale, "unacceptable thoughts", and "symmetry" sub-scales were 0.874, 0.932, 0.933, 0.948, 0.921, respectively. There was a high correlation between It has been determined that there is high correlations between both total scores and sub-scales scores of DOCS, YBOCS and PI. Conclusions: Internal consistencies were high good for the total scale and very high perfect for the sub-scales. The factor structure and the contents of the factors were perfectly in line with the original scale (i.e. 4 factor). Positive correlations between DOCS, its sub-scales, and similar OCD scales suggest that the DOCS accurately measures the structures it claims to assess. Thus the DOCS Turkish version can measure dimensional obsessive compulsive symptoms among the Turkish speaking OCD population. © 2018 Turkish Association of Nervous and Mental Health

Relationship between low-frequency electromagnetic field and computer vision syndrome

OBJECTIVE: This study aimed to determine the prevalence of computer vision syndrome (CVS) among secretaries working in different departments of a university hospital in Turkey and its relationship with low-frequency electromagnetic field (LF-EMF) exposure. SUBJECTS AND METHODS: This cross-sectional study included 143 secretaries working in different departments of the hospital. Besides eye examinations, CVS Syndrome Questionnaire (CVS-Q) Scale and Ocular Surface Disease Index Scale (OSDI) were applied to the participants. LF-EMF of the work environment were measured with a 6010 Gauss/Teslameter device and the light intensity with an LX-1102 Device. RESULTS: The mean age of participants was 39.6 years, with a male-to-female ratio of 25.2% to 74.8%. CVS-Q scale revealed 83.9% of computer vision syndrome among participants. A weak positive correlation was found between CVS-Q and LF-EMF, while a moderately strong, negative correlation was found between LF-EMF and Schirmer test of both eyes. The work environment LF-EMF values were significantly higher among the participants diagnosed with CVS (p1,725 µT and an increase of 0.004 units in the CVS-Q score was calculated for each one-unit increase in the LF-EMF of the environment. CONCLUSIONS: A relationship between CVS, dry eye and EMF was observed among people exposed to LF-EMF. Regular measurement of EMF in work environments, and developing protective behaviours (work-break intervals, 20-20-20 rule, etc.) can be recommended

Ankara İlinde Bati Nil Virusu Köken-1 Kaynakli Bir Merkezi Sinir Sistemi Enfeksiyonu Olgusu

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Preparedness and Preventive Behaviors for a Pandemic Disaster Caused by COVID-19 in Serbia

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2. The disease was first detected in Wuhan, the capital of China’s Hubei province, in December 2019 and has since spread globally, especially to Europe and North America, resulting in the ongoing global coronavirus pandemic disaster of 2019–2020. Although most cases have mild symptoms, there is some progression to viral pneumonia and multi-organ failure and death. More than 4.6 million cases have been registered across 216 countries and territories as of 19 April 2020, resulting in more than 311,000 deaths. Risk to communities with continued widespread disease transmission depends on characteristics of the virus, including how well it spreads between people; the severity of resulting illness; and the medical or other measures available to control the impact of the virus (for example, vaccines or medications that can treat the illness) and the relative success of these. In the absence of vaccines or medications, non-pharmaceutical interventions were the most important response strategy based on community interventions such as person-to-person distancing, mask-wearing, isolation and good personal hygiene (hand-washing)—all of which have been demonstrated can reduce the impact of this seemingly unstoppable globally spreading natural disaster. This paper presents the results of quantitative research regarding the level of citizen preparedness for disasters caused by coronavirus disease (COVID-19) in Serbia. The survey was conducted using a questionnaire that was requested and then collected online among 975 respondents during disaster in April 2020. The questionnaire examined citizens’ basic socio-economic and demographic characteristics, their knowledge, preparedness, risk perception and preventive measures taken individually and as a community to prevent the death and widespread transmission of novel coronavirus disease 2019 in the Republic of Serbia. Based on the findings that there are major differences in the public’s perception of risks posed by communicable disease threats such as presented by COVID-19, emergency management agencies should use these differences to develop targeted strategies to enhance community and national preparedness by promoting behavioral change and improving risk management decision-making

Multicenter Investigation Of Bufavirus In The Etiology Of Viral Central Nervous System Infections Of Adults And Children | Bufavirusun Çocuklar Ve Erişkinlerdeki Viral Santral Sinir Sistemi Enfeksiyonlarinin Etiyolojisi Açisindan Çok Merkezli Olarak Araştirilmasi

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